SDS-tolerant soybean varieties for Iowa

Last year we began testing soybean varieties for tolerance to sudden death syndrome (SDS). Funded by checkoff dollars, we have repeated the test this year with varieties submitted to us by private companies.

The SDS tolerance test was conducted in a field near Ames, Iowa. To ensure uniform and consistent disease pressure across plots, we planted dry oats infested with the SDS pathogen along with the soybean seed. Our field experiments show this method, developed by our project at Iowa State University, can provide a consistent level of disease pressure. Details of this method are available upon inquiry.

Lines were planted in plots consisting of two 10-foot-long rows at eight seeds per foot with a row spacing of 30 inches. Lines were replicated three times. Plots were evaluated in early September and each line was given a numerical tolerance score from 0 to 10 based on leaf symptoms, with 10 indicating 100% defoliation. Low scores indicate a high level of tolerance. Most entries in our tests are tolerant to this disease.

Disease pressure this year was less than that of 1999 due to dry conditions in late summer and in general, yields were poor. Varieties with ratings of 3 or 4 show some level of susceptibility to the disease compared with susceptible controls. If you want to compare this year-s results with those in 1999, information can be found in November 8, 1999, ICM newsletter.

SDS Tolerance Test 2000

Company Variety Maturity Disease Score Mean Yield Mean

(bu/acre)
Agripro 2569 2.5 0 41.5
Asgrow AG3201 3.2 3 44.7
Bio-plant 8298 3.0 2 45.3
Dairyland DSR-232/RR 2.3 0 40.2
Dairyland DSR-254/RR 2.5 1 40.3
Dairyland DSR-275 2.7 2 42.5
Dairyland DSR-218 2.1 0 41.7
Dekalb DKB32-51 3.2 2 37.0
Dekalb CX284c 2.8 1 47.6
Latham 527 RRN 1 42.3
Latham 667 RRN 1 42.5
Latham 830 1 43.9
Mark 9519 CTA 0 40.7
Mark 9922 CTA 1 40.1
Merchman Fillmore VRR 3.4 3 34.6
Merchman Madison III 3.5 2 42.9
Merchman Hoover IVRR 3.0 2 40.1
Merchman Truman VI 3.4 3 44.4
NC+ Hybrids 3A19RR 3.1 2 42.1
NC+ Hybrids 3A77RR 3.7 3 32.5
NC+ Hybrids 3N28RR 3.2 2 37.3
NC+ Hybrids 3A40RR 3.4 2 35.4
Novartis X030 3.0 3 45.3
Novartis X026R 2.6 0 43.6
Novartis S30-P6 3.0 3 44.9
Novartis S38-T8 3.8 3 37.6
Ottilie RO Seed 8330 3.3 2 41.2
Ottilie RO Seed 8271 2.7 1 49.6
Ottilie RO Seed 8340 RR 3.4 2 35.3
Ottilie RO Seed 8252 RR 2.5 1 44.7
Pioneer 93B26 3.2 1 44.8
Pioneer 93B82 3.8 3 39.4
Pioneer 93B71 2.7 0 37.9
Pioneer 9306 3.0 0 39.7
Sand Seed Service SOI 244 RR 2.4 0 37.3
Sand Seed Service SOI 344 RR 3.4 3 35.8
Sieben SS 289 2.8 1 45.0
Sieben SS 319 3.1 4 40.3
Sieben SS 279 2.7 1 36.3
Sieben SS 2703 RR 2.7 1 38.1
Stine Seed Co. 3503-4 4 33.3
Stine Seed Co. 3763-4 4 33.9
Stine Seed Farms 3000-0 1 43.1
Stine Seed Farms 3398-8 3 45.3
Wilson 3277 RR 3.2 2 38.7
Wilson 2740 RR 2.7 1 39.6
Tolerance check Ripley 1 51.3
Susceptible check Spencer 2 48.2
Susceptible check P9344 3 30.0

This article originally appeared on pages 197-198 of the IC-484(25) -- December 18, 2000 issue.

Updated 12/17/2000 - 1:00pm